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May 27, 2017

Granularity of space-time is an outstanding issue

Theory of relativity has been verified by physical experimental equipment which you touch and adjust with your hands, not just mathematical formulas. What I was pointing out was that both theory of relativity and quantum mechanics work to a super extent in the domain in which they are expected to be independently valid. The conflict and uncertainty arise when both are expected to be important such as at the time of big bang and in black holes. Otherwise there is no problem.

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When you try to express a highly mathematical theory like general theory of relativity in terms of ordinary non mathematical human languages some issues surely come up. But most physicists accept the language that in presence of a mass, surrounding space, which was flat before, becomes curved. The space has many properties as if you are on a surface of a sphere and not on a flat plane.

Any one is welcome to have his/her own opinions. There should not be any censorship. But if you say theory of relativity is totally wrong, you will have hard time convincing overwhelming number of physicists!

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Dear Vinod,

I joined this group to understand Vedas and consciousness. But to my surprise, lot of physics questions keep on coming up and I enjoy participating in these. I will try to answer your questions with a caution that some of these are at the forefront of research and borderline between metaphysics and physics and highly controversial. The main point is that in physics, one looks at the data, makes mathematical model and calculates to see if the consequences agree with experiments. Otherwise one has to refine the model or give up on that particular model. It has not been easy to put mathematical models of modern physics in terms of human languages. Very often words cannot describe what you are doing mathematically!

In my article I compare this to difficulties which Rishis faced when they tried to explain Brahman and finally said “Neti, Neti”! For most physicists agreeing with experiments with mathematical models is an end in itself. They could not care less if you can put them in terms of human languages or not!! Only a few care about meaning of the equations.

“i) If the curvature of the space ( spacetime) is a real physical phenomenon, what is in the space which undergoes curvature?”

Einstein’s relativity replaced Newton’s law of gravity by an equation which predicts precisely how the space will be curved as a result of presence of matter. The matter particle has to follow that path as the path itself is curved. I like to give the following example. Consider a train on railway track which is curved. The engine driver does not have to turn the steering wheel. The train will automatically follow the track. In Newton’s explanation, the planets follow curved path around the sun because of the gravitational force. In Einstein’s world the curvature comes out naturally just as if you keep driving on the surface of earth, you cannot go straight. Your path will be curved by nature. Einstein had to use what is known as Riemannian geometry instead of Euclidian geometry which we learn in high school. Our everyday straight paths are possible only in Euclidean geometry (flat space). Other than that it is hard to put in words what happens to space.

“What is in the matter in terms of its particles which affects space?” “If the curvature of space ( spacetime) is a real phenomenon, some interacting force must exist between matter and space? What is the nature of that force and how that force originates?”

It is believed that there are particles called gravitons like light particles called photons. Exchange of this between particles causes gravitational force and curvature of space around the particles. When there is a satisfactory theory of merger between quantum theory and theory of relativity (called quantum gravity) we will understand this better. Nobody has observed gravitons. But there is very little doubt about existence of these. As yet there is no satisfactory theory of quantum gravity in the sense that you can calculate some process and experimentally verify that. Granularity of space-time is also an outstanding issue.

I trust this will be satisfactory up to a point in terms of non-mathematical human language!! Why mathematics works when human languages fail is a deep philosophical problem.

Best regards.

kashyap

May 27, 2017

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Hi Norm,

Please feel free to call me kashyap!

Of course the most earth shaking consequence of relativity (E=mc^2) is nuclear energy, both atom bombs and power reactors. So I cannot give you an instrument in your hands which uses E=mc^2!! directly. But there are instruments used in medical practice (called nuclear medicine, google it) which are based on radioactive decay. These are results of E=mc^2!

This kind of constant revision is part of scientific method. Even when we have a final theory of “quantum gravity” all the previous theories would be true in some domains as approximations and their successes would still remain. I am sure you know that transistors which came out of quantum theory gave rise to multibillion dollar industry. The computer on which I am writing this reply uses chips involving transistors.

Best regards.

kashyap
May 28, 2017
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Dear Siegfried

I would be really grateful if you or Kashyap could elucidate a related issue that I have with relativity theory. It concerns the famous twins paradox where one twin racing away from the earth close to light speed will perceive the other twins 'clocks' going slower. And the twin on earth looking through a powerful telescope will perceive the space twin's clock's also going slower by the same amount due to special relativity. I have always understood that when the space twin swings round a nearby star and returns to earth he will arrive back somewhat younger than his sibling due essentially to the effects of general relativity caused by the accelerations he undergoes.

My question is: What if he turns round by some means that does not involve gravity? What if his rocket still has enough fuel to slow him down and blast him back in the opposite direction? Will he still arrive back younger than his sibling? And if so does that not mean there is an element of spacetime curvature associated with any acceleration (even those experienced by particles in the centrifuge you have been discussing)?